Single cavity multisegment magnetron



Nov. 29, 1949 c. l. sHuLMAN 2,490,008

SINGLE CVITY MULTI-SEGMENT MAGNETRON Filed Jan. 7, 1947 2 sheets-sheet 1 'n Imi ...m

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SINGLE CAVITY MULTISEGMENT MGNETRON VFiled Jan. '7, 1947 2 Sheets-Sheet 2 J7 ,ul/gy] nuentor v ttomeg 3 of the block I2 at one end. At the other end the resonators open into the interaction space surrounding the cathode I and are open also on both sides in the direction transverse to the block I2. In this manner there is an electro-magnetic intercoupling between the resonators. The varies I4 are also strapped together by means of conducting rings I'I and I8 which are connected to alternate varies to enhance operation in the desired mode. The cathode I5 is supported by means of the disc I9 made of magnetic material and secured to a yoke member 20. A similari yoke 2I is provided on the other side of the anode block I 2. Both yokes are supported on the anode block I2 by means of insulating bushings, 22 and 23, preferably of ceramic material, and bolts 24 and 25, respectively. The cathode I5 i-s also insulated from the yoke 2U by means of the insulating bushing 26 held in the disc I9. Between the anode block I2 and the yoke 20 and mounted thereon by means of insulating washers 28 and screws 29 is a circular plate member 3I of approximately the same diameter as the circular opening I3. The function of this plate member will be explained later.

The yoke 2l has a longitudinally expanding slot 32 which holds a pair of electron beam emitting elements so constructed as to t easily into the slot for simple assembly. The particular construction of the electron emitting elements will be better understood by referring to the enlarged per-spective view of Fig. 6 and the crosssectional view of Fig. 7. The electron beam emitters 33 are essentially individual triode assemblies having specially constructed and shaped elements. The entire assembly is built around a U-shaped member 94 which is provided with ilanges along its longitudinal sides and an elongated aperture 33 in its flat side. Two insulating plates 35 and 35 which may be of mica or simila` material are held by the member 34 by means of turned down iiaps 3'I and between these plates is mounted an indirectly heated cathode sleeve 38 The output of the magnetron may be taken oi surrounded by a grid winding 39 wound on rods Y more, the anges of this member t into a recess in the yoke 2I whereby the entire assembly is centered and held in place without other mounting means or holes which otherwise would have to be drilled with precision in parts of the magnetron.

In the gures showing the complete magnetron it is seen that the two beam emitters 33 are so arranged as to be juxtaposed with certain resonators of the anode block. In this manner the acceleratingv electrode 34 has its aperture 30 so directed as to introduce an electron beam in the direction transverse to the anode block I2 into and through the cavity of certain resonators. The function of the plate 3I previously described is to collect the electrons of the beams. single plate 3| eliminates the need of separate beam collecting electrodes for each emitter. In this manner several electron emitters may be used with one electron collecting electrode.

A disc 42 of magnetic material, similar to the disc I9, is secured against the yoke 2I and presses also against the flanges of the member 34 whereby the emitters are firmly held in place. The disc-s I9 and 42 being of magnetic material serve as internal magnetic members for the field pro- The through the sealed-in output electrode 48 which terminates in a coupling loop 49 in one of the resonators.

It is to be noted also that the cover 45 has a tubular portion 50 which is closed by a cover seal 5I. In line with the portion 50 there is an opening 52 in the anode block I2 which communicates with one of the resonator cavities. This opening, together with the portion 59, may be used for assembling a tuning device on the magnetron of the type disclosed in an application Serial No. 711,683, filed November 22, 1946, in the name of J. Kurshan, assigned to Radio Corporation of America. The tuning mechanism and method of operation described in the above application may readily be adapted to the magnetron structure herein disclosed, in which case it replaces the cover seal 5 I I claim:

1. An electron discharge device including a cavity resonator subjected to a magnetic field, means for directing an electron beam in the direction parallel to said eld into said resonator along a predetermined path comprising an electron gun assembly adjacent said reso-nator and including an accelerating electrode having an aperture, a pair of insulating members alxed to said electrode, an electron emitting cathode and a grid electrode inside said accelerating electrode and supported from said members in alignment with said aperture, and an electron collecting electrode oppositeiy disposed to said gun and in said path.

2. An electron discharge device including a cavity resonator subjected to a magnetic field, means for directing an electron beam in the direction parallel to said field into said resonator along a predetermined path comprising an electron gun assembly adjacent said resonator and including an elongated U-shaped accelerating electrode flanged outwardly having an elongated aperture, a pair of insulating members closing both ends of said electrode, supports extending between said members, a grid electrode helically wound on said supports and an electron emitting cathode inside said grid and extending between said members in alignment with said aperture, a support for said assembly comprising a. plate member adjacent one end of said resonator, said plate member having a longitudinal aperture accommodating said U- shaped electrode and a recess accommodating said flanges and an electron collecting electrode adjacent said resonator and in said path.

3. A magnetron discharge device including a cathode, an anode electrode surrounding said cathode having a plurality of cavity resonators spaced around said cathode and open on both sides of said anode, a rst yoke member adjacent one side of said anode and insulated therefrom, a second yoke member adjacent the other side of said anode and insulated therefrom, a pair of electron emitting elements supported by said rst yoke member, each of said elements being oriented in juxtaposition with one of said resonators whereby the electrons emitted from said elements pass through the cavity of said resonators and a plate electrode for collecting said electrons supported by said second yoke member.

4. A magnetron discharge device including a cathode, an anode electrode surrounding said cathode having a plurality of cavity resonators radially spaced around said cathode and open on both sides of said anode, a rst yoke member adjacent one side of said anode and insulated therefrom, a second yoke member adjacent the other side of said anode and insulated therefrom, a pair of electron emitting ele-ments comprising a cathode, a grid and an accelerating electrode spaced equidistantly from said cathode and supported by said first yoke member, each of said elements being oriented in juxtaposition with one of said resonators whereby the electrons emitted from said elements pas-s through the cavity of said resonators and a disc shaped electrode having a diameter substantially equal to the spacing between said elements for collecting said electrons supported by said second yoke member.

5. The structure in accordance with claim 3 wherein each of said electron emitting elements comprises an assembly including a cathode, a grid electrode, and an accelerating electrode in the form of a longitudinally extending U-shaped member flanged on both longitudinal sides and having a longitudinally extending aperture, a pair of insulating plates attached to the ends of said U-shaped member, lsaid cathode and grid electrode being mounted inside said U-shaped member in alignment with said aperture on supports held between said plates, said rst yoke member having a longitudinally extending slot accommodating said U-shaped member and a vertically extending recess accommodating said flanges.

6. A magnetron discharge device including a base header, an oblong metal anode electrode mounted on said header, said electrode having a circular aperture divided into sectors each of which opens into a central space and surrounds a cathode electrode transverse to said anode, said sectors forming resonators, first and second yokes, one member on each side of said electrode and parallel therewith, supporting means for said yokes comprising insulating bushings secured to each side of said anode, said yokes being fastened to said bushings thereby being insulated from said anode, a disc of magnetic material fastened to said second yoke on one side, an insulating bushing traversing said second yoke and supported in said disc, said bushing surrounding said cathode electrode, a circular plate electrode mounted on the other side of said second yoke and insulated therefrom, said plate electrode having a diameter substantially equal to that of said aperture, a pair of electron beam forming elements mounted on said iirst yoke and oriented in the direction to form an electron beam transverse to said anode electrode and through a pair of said sectors, said circular plate `electrode being adapted to collect the electrons oi the beams emitted from said elements, a plurality of terminals sealed in said header and connections from said terminals to said cathode electrode, to said plate electrode, and to said beam forming elements,

7. A'magnetron discharge device including a base header, an oblong metal anode electrode mounted on said header, said electrode having a circular aperture divided into sectors each of which opens into a central space and surrounds a cathode electrode transverse to said anode, said sectors forming resonators, rst and second yokes, one on each side of said anode electrode and parallel therewith, supporting means for said yokes comprising insulating bushings secured to each side of said anode electrode, said yokes being fasu tened to said bushings thereby being insulated from said anode electrode, a disc of magnetic material fastened to said second yoke on one side, an insulating bushing traversing said second yoke and supported in said disc, said bushing surrounding said cathode electrode, a circular plate electrode mounted on the other side of said second yoke and insulated therefrom, said plate electrode having a diameter substantially equal to that of said aperture, a pair of electron beam forming elements each comprising cathode, grid and accelerating electrodes mounted on said rst yoke, said accelerating electrodes having apertures oriented in the direction to form electron beams transverse to said anode electrode and directed through a pair of said resonators, said circular plate electrode being adapted to collect the electrons of the beams emitted from said elements, a second disc of magnetic material fastened to said first yoke, said discs providing internal magnetic materials for a eld producing magnet, a plurality of terminals sealed in said header and connections from said terminals to said cathode electrode, said plate electrode, and to the electrodes of said beam forming elements.

8. The structure in accordance with claim 3 wherein each of said electron emitting elements comprises an assembly consisting of an accelerating electrode in the form of a longitudinally extending U-shaped member flanged on both its longitudinal sides and having a longitudinally extending aperture, a pair of insulating plates attached to the ends of said accelerating electrode, a cathode and grid electrode mounted inside said accelerating electrode in alignment with said aperture, said cathode comprising a thoriated sleeve extending through said plates and accommodating heater wires inside said sleeve, said grid electrode being a winding over a pair of rods parallel to said cathode and extending through said plates and said rst yoke member having a longitudinally extending cut-out portion accommodating said U-shaped member and a vertically extending recess accommodating said langes, and a disc of magnetic material secured to said first yoke member and resting over said anges.

9. A magnetron discharge device including a cathode, an anode electrode surrounding said cathode having a plurality of cavity resonators spaced around said cathode and open on both sides of said anode, a plurality of electron emitting elements, means supporting each of said elements adjacent one side of said anode and oriented in juxtaposition with one of said resonators whereby the electrons emitted from said elements pass through said resonators, and a plate electrode mounted adjacent the other side of said anode for collecting said electrons.

CARL I. SHULMAN.

REFERENCES CITED The following references are of record in the i'lle of this patent:

Proceedings I. R. E., July 1947, pages 644-657, original manuscript received by the Institute, Apr. 26, 1946. 

